What Is Rising Damp in Walls?

Rising damp occurs when groundwater travels upward through the capillaries of masonry materials such as brick, stone, or concrete. This capillary action allows liquid water to migrate vertically from the ground into the wall structure, often resulting in visible and damaging effects over time.

Understanding and Treating Rising Damp in Masonry Walls

One of the most common signs of rising damp is a horizontal tide mark, typically appearing up to one metre above ground level. This mark indicates the height to which moisture has risen. In addition, salts carried by the water, particularly nitrates and chlorides, are deposited on the wall surface as the moisture evaporates. This phenomenon is known as efflorescence. Over time, these salts crystallise and expand, causing the surface of the wall to deteriorate, flake, or crumble. Left untreated, rising damp can compromise both the aesthetic and structural integrity of a building.

A Modern Solution: Damp-Course Cream

The only reliable, permanent solution for rising damp is installing a new damp course. This barrier sits at the base of the wall and stops further moisture from entering. Traditionally, workers removed bricks or injected liquid chemicals with limited penetration. These methods were invasive and disruptive.

However, a more advanced and less invasive option now exists. It uses a high-performance silicone cream. This cream contains a concentrated blend of active silanes. Once injected into the mortar line, it penetrates deeply into the masonry. As the cream spreads, it reacts with the wall to form a water-repellent layer through the entire thickness. This new barrier works as an effective damp course. It halts moisture movement while preserving the wall’s appearance and breathability.

An innovative example is Tech-Dry’s Damp-Course Cream. It uses a high concentration of active silanes to penetrate the wall fully and create a water-repellent layer. This product offers a long-lasting, low-impact solution for rising damp in residential, heritage, and commercial buildings.